1. Technical Field
The present invention relates to an image processing apparatus, an image processing method, and a computer readable medium storing an image processing program.
2. Related Art
A known image processing apparatus includes an illumination light component estimation unit that calculates an estimated illumination light component of an original image, an estimated illumination light component correction unit that outputs a corrected estimated illumination light component obtained by correcting the estimated illumination light component, a Retinex processing unit that corrects a brightness component by dividing the brightness component of the original image by the corrected estimated illumination light component, and a gain adjustment unit that adjusts the gain of the corrected brightness component (for instance, see JP-A-2012-108898). The estimated illumination light component correction unit converts an estimated illumination light component having a value from 0 to a reference value to a maximum value of the corrected estimated illumination light component, converts an estimated illumination light component having a value larger than the reference value such that the value of the corrected estimated illumination light component is larger than the value of the estimated illumination light component, and uses such a property that the rate of increase in the corrected estimated illumination light component decreases as the value of the estimated illumination light component increases.